From contact investigation to tuberculosis screening of drug addicts and homeless persons in Rotterdam

Use of targeted mobile X-ray screening and computer-aided detection software to identify tuberculosis among high-risk groups in Romania: descriptive results of the E-DETECT TB active case-finding project

OBJECTIVE

To implement and assess the mobile X-ray unit (MXU) equipped with digital radiography, computer-aided detection (CAD) software and molecular point of care tests to improve early tuberculosis (TB) diagnosis in vulnerable populations in a TB outreach screening programme in Romania.

DESIGN

Descriptive study.

SETTINGS

Prisons in Bucharest and other cities in the southern part of Romania, homeless shelters and services for problem drug users in Bucharest, and Roma populations in Bucharest and Craiova.

PARTICIPANTS

5510 individuals attended the MXU service; 5003 persons were radiologically screened, 61% prisoners, 15% prison staff, 11% Roma population, 10% homeless persons and/or problem drug users and 3% other.

INTERVENTIONS

Radiological digital chest X-ray (CXR) screening of people at risk for TB, followed by CAD and human reading of the CXRs, and further TB diagnostics when the pulmonologist classified the CXR as suggestive for TB.

PRIMARY AND SECONDARY OUTCOME MEASURES

Ten bacteriologically confirmed TB cases were identified translating into an overall yield of 200 per 100 000 persons screened (95% CIs of 109 to 368 per 100 000). Prevalence rates among homeless persons and/or problem drug users (826/100 000; 95% CI 326 to 2105/100 000) and the Roma population (345/100 000; 95% CI 95 to 1251/100 000) were particularly high.

RESULTS

The human reader classified 6.4% (n=317) of the CXRs as suspect for TB (of which 32 were highly suggestive for TB); 16.3% of all CXRs had a CAD4TB version 6 score >50. All 10 diagnosed TB patients had a CAD4TB score >50; 9 had a CAD4TB score >60.

CONCLUSIONS

Given the high TB prevalence rates found among homeless persons and problem drug users and in the Roma population, targeted active case finding has the potential to deliver a major contribution to TB control in Romania.

Prevalence of latent tuberculosis infection and HIV among people who inject drugs in Iran

INTRODUCTION

Iran has an human immunodeficiency viruses (HIV) epidemic that is concentrated among people who inject drugs (PWID), who have higher risks of progression from latent tuberculosis infection (LTBI) to active disease. The aim of this study is to measure prevalence of LTBI, HIV infection and any risk behaviors among PWID in Iran.

METHODS

The cross-sectional study was conducted from August to December 2013 in six cities across Iran. A total of 420 PWID were recruited from drop-in centres using convenience sampling. Trained interviewers collected data on socio-demographic characteristics, drug use history and drug-related risk behaviors across the study sites. A tuberculin skin test (TST) was performed, and HIV infection was assessed by a rapid test. Multivariable modified Poisson regression and logistic regression were used for data analysis.

RESULTS

Prevalence of positive TST and HIV positivity was 35.7% and 8.6%, respectively. The prevalence of LTBI and HIV was significantly different across the cities of this study. Positive TST was independently associated with older age (APR 1.03, 95% CI 1.01, 1.05) and being HIV positive (APR 1.89, 95% CI 1.45, 2.47). HIV infection was associated with lifetime history of sharing syringes (AOR 3.28, 95% CI 1.44, 10.71) and lifetime number of imprisonment (AOR 1.09, 95% CI 1.03-1.14).

DISCUSSION AND CONCLUSIONS

Prevalence of LTBI infections among PWID is high and independently associated with HIV infection. Given that there are currently no TB services available within drop-in centres, programs which integrate TB case finding, TB preventive therapy, referral and care services for PWID are urgently needed.

Management and control of tuberculosis control in socially complex groups: a research programme including three RCTs

Background

Socially complex groups, including people experiencing homelessness, prisoners and drug users, have very high levels of tuberculosis, often complicated by late diagnosis and difficulty in adhering to treatment.

Objective

To assess a series of interventions to improve tuberculosis control in socially complex groups.

Design

A series of observational surveys, evaluations and trials of interventions.

Setting

The pan-London Find&Treat service, which supports tuberculosis screening and case management in socially complex groups across London.

Participants

Socially complex groups with tuberculosis or at risk of tuberculosis, including people experiencing homelessness, prisoners, drug users and those at high risk of poor adherence to tuberculosis treatment.

Interventions and main outcome measures

We screened 491 people in homeless hostels and 511 people in prison for latent tuberculosis infection, human immunodeficiency virus, hepatitis B and hepatitis C. We evaluated an NHS-led prison radiographic screening programme. We conducted a cluster randomised controlled trial (2348 eligible people experiencing homelessness in 46 hostels) of the effectiveness of peer educators (22 hostels) compared with NHS staff (24 hostels) at encouraging the uptake of mobile radiographic screening. We initiated a trial of the use of point-of-care polymerase chain reaction diagnostics to rapidly confirm tuberculosis alongside mobile radiographic screening. We undertook a randomised controlled trial to improve treatment adherence, comparing face-to-face, directly observed treatment with video-observed treatment using a smartphone application. The primary outcome was completion of ≥ 80% of scheduled treatment observations over the first 2 months following enrolment. We assessed the cost-effectiveness of latent tuberculosis screening alongside radiographic screening of people experiencing homelessness. The costs of video-observed treatment and directly observed treatment were compared.

Results

In the homeless hostels, 16.5% of people experiencing homelessness had latent tuberculosis infection, 1.4% had current hepatitis B infection, 10.4% had hepatitis C infection and 1.0% had human immunodeficiency virus infection. When a quality-adjusted life-year is valued at £30,000, the latent tuberculosis screening of people experiencing homelessness was cost-effective provided treatment uptake was ≥ 25% (for a £20,000 quality-adjusted life-year threshold, treatment uptake would need to be > 50%). In prison, 12.6% of prisoners had latent tuberculosis infection, 1.9% had current hepatitis B infection, 4.2% had hepatitis C infection and 0.0% had human immunodeficiency virus infection. In both settings, levels of latent tuberculosis infection and blood-borne viruses were higher among injecting drug users. A total of 1484 prisoners were screened using chest radiography over a total of 112 screening days (new prisoner screening coverage was 43%). Twenty-nine radiographs were reported as potentially indicating tuberculosis. One prisoner began, and completed, antituberculosis treatment in prison. In the cluster randomised controlled trial of peer educators to increase screening uptake, the median uptake was 45% in the control arm and 40% in the intervention arm (adjusted risk ratio 0.98, 95% confidence interval 0.80 to 1.20). A rapid diagnostic service was established on the mobile radiographic unit but the trial of rapid diagnostics was abandoned because of recruitment and follow-up difficulties. We randomly assigned 112 patients to video-observed treatment and 114 patients to directly observed treatment. Fifty-eight per cent of those recruited had a history of homelessness, addiction, imprisonment or severe mental health problems. Seventy-eight (70%) of 112 patients on video-observed treatment achieved the primary outcome, compared with 35 (31%) of 114 patients on directly observed treatment (adjusted odds ratio 5.48, 95% confidence interval 3.10 to 9.68; p < 0.0001). Video-observed treatment was superior to directly observed treatment in all demographic and social risk factor subgroups. The cost for 6 months of treatment observation was £1645 for daily video-observed treatment, £3420 for directly observed treatment three times per week and £5700 for directly observed treatment five times per week.

Limitations

Recruitment was lower than anticipated for most of the studies. The peer advocate study may have been contaminated by the fact that the service was already using peer educators to support its work.

Conclusions

There are very high levels of latent tuberculosis infection among prisoners, people experiencing homelessness and drug users. Screening for latent infection in people experiencing homelessness alongside mobile radiographic screening would be cost-effective, providing the uptake of treatment was 25–50%. Despite ring-fenced funding, the NHS was unable to establish static radiographic screening programmes. Although we found no evidence that peer educators were more effective than health-care workers in encouraging the uptake of mobile radiographic screening, there may be wider benefits of including peer educators as part of the Find&Treat team. Utilising polymerase chain reaction-based rapid diagnostic testing on a mobile radiographic unit is feasible. Smartphone-enabled video-observed treatment is more effective and cheaper than directly observed treatment for ensuring that treatment is observed.

Future work

Trials of video-observed treatment in high-incidence settings are needed.

Trial registration

Current Controlled Trials ISRCTN17270334 and ISRCTN26184967.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 8, No. 9. See the NIHR Journals Library website for further project information.

Challenges posed by COVID-19 to people who inject drugs and lessons from other outbreaks

INTRODUCTION

In light of the COVID-19 pandemic, considerable effort is going into identifying and protecting those at risk. Criminalization, stigmatization and the psychological, physical, behavioural and economic consequences of substance use make people who inject drugs (PWID) extremely vulnerable to many infectious diseases. While relationships between drug use and blood-borne and sexually transmitted infections are well studied, less attention has been paid to other infectious disease outbreaks among PWID.

DISCUSSION

COVID-19 is likely to disproportionally affect PWID due to a high prevalence of comorbidities that make the disease more severe, unsanitary and overcrowded living conditions, stigmatization, common incarceration, homelessness and difficulties in adhering to quarantine, social distancing or self-isolation mandates. The COVID-19 pandemic also jeopardizes essential for PWID services, such as needle exchange or substitution therapy programmes, which can be affected both in a short- and a long-term perspective. Importantly, there is substantial evidence of other infectious disease outbreaks in PWID that were associated with factors that enable COVID-19 transmission, such as poor hygiene, overcrowded living conditions and communal ways of using drugs.

CONCLUSIONS

The COVID-19 crisis might increase risks of homelessnes, overdoses and unsafe injecting and sexual practices for PWID. In order to address existing inequalities, consultations with PWID advocacy groups are vital when designing inclusive health response to the COVID-19 pandemic.

Tuberculin skin test and predictive host factors for false-negative results in patients with pulmonary and extrapulmonary tuberculosis

INTRODUCTION

Tuberculin skin test (TST) has been the standard test for screening for Mycobacterium tuberculosis infection for decades. Identifying persons with latent tuberculosis infection (LTBI) is crucial, as they constitute a reservoir that sustains the global tuberculosis (TB) epidemic. However, different factors, such as HIV infection, can lower the sensitivity of the test.

OBJECTIVES

The aim of this study was to determine the TST sensitivity in active TB patients and to ascertain risk factors that could be associated with false-negative results.

METHODS

Retrospective cohort study of all active TB notifications with a TST result (n = 8833), from 2008 to 2015. TST results were interpreted using a 5 mm and 10 mm cutoff. Bivariate and multivariate logistic regression analysis were used to evaluate the association of sociodemographic and clinical factors with false-negative TST results and to develop predictive risk models.

RESULTS

TST presented an overall sensitivity of 63.8% (5 mm) and 56.1% (10 mm). HIV infection was the risk factor with the strongest association with false-negative results (aOR 4.65-5 mm; aOR 5.05-10 mm). Other factors such as chronic renal failure (CRF) (aOR 1.55-5 mm; aOR 1.73-10 mm), alcohol abuse (aOR 1.52-5 mm; aOR 1.31-10 mm), drug abuse (aOR 1.90-5 mm; aOR 1.76-10 mm) or age ≥65 years (OR 1.69-5 mm and 10 mm) were also associated with a probability of false-negative results.

CONCLUSION

These results highlight the importance of knowing which factors influence TST results, such as HIV status, substance abuse or age, thus improving its usefulness as a screening method for LTBI.

Contact tracing strategies in household and congregate environments to identify cases of tuberculosis in low- and moderate-incidence populations

BACKGROUND

Tuberculosis is an infectious bacterial disease that is spread via respiratory droplets from infected individuals to susceptible contacts. To eliminate this disease from low- and medium-incidence settings, people who are most likely to be infected (contacts) must be identified. Recently, study authors have examined alternate approaches to contact tracing methods that demonstrate improved detection and prioritization of contacts. The comparative benefit of these methods has not been established.

OBJECTIVES

To assess the effectiveness of novel methods of contact tracing versus current standard of care to identify latent and active cases in low- to moderate-incidence settings.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, Web of Science, and CINAHL up to 15 July 2019. We also searched for clinical trials and examined reference lists and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and cluster-RCTs of contact tracing strategies that included alternate approaches (other than standard practice).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed identified articles for eligibility and quality using prespecified criteria.

MAIN RESULTS

No trials met the inclusion criteria of this review. Several study authors described an alternate method for examining contacts and performing social network analysis but did not compare this with the current contact tracing approach.

AUTHORS' CONCLUSIONS

This Cochrane Review highlights the lack of research in support of the current contact tracing method and the need for RCTs to compare new methods such as social network analysis to improve contact tracing processes.

Chest x-ray findings in tuberculosis patients identified by passive and active case finding: A retrospective study

Background

Chest x-ray is central in screening and diagnosis of tuberculosis. However, sputum culture remains gold standard for diagnosis.

Aim

To establish the rate of normal chest x-rays in tuberculosis patients found by spot sputum culture screening, and compare them to a group identified through passive case finding.

Method

Chest x-rays from 39 culture-positive patients, identified by spot sputum culture screening in Copenhagen from 2012 to 2014, were included in the study (spot sputum culture group(SSC)). 39 normal chest x-rays from persons screened by mobile x-ray, and 39 chest x-rays from tuberculosis-patients identified through passive case finding(PCF) were anonymised and randomised. Two respiratory physicians and two radiologists assessed the chest x-rays.

Results

The normal chest x-ray rate was higher in the non-tuberculosis control group (median = 32 (82.1%), range = 74.4% – 100%), compared to the SSC group (median = 7 (17.9%), range = 10.3% – 33.3%), and the PCF controls (median = 3(7.7%), range = 2.6% – 15.4%). In the SSC group 14 (35.9%) were categorized as normal by at least one study participant.

Conclusion

A substantial minority of patients diagnosed with tuberculosis by spot sputum culture screening, and through passive case finding would not have been identified with chest x-ray alone, highlighting that a normal chest x-ray does not exclude pulmonary tuberculosis.

Interventions to improve contact tracing for tuberculosis in specific groups and in wider populations: an evidence synthesis

Background

The tracing and screening of people who have had contact with an active case of tuberculosis (TB) is an important element of TB control strategies.

Objectives

This study aimed to carry out a review of evidence regarding TB contact tracing, with a particular emphasis on research that was applicable to TB contact tracing in specific population groups in the UK.

Design

An evidence synthesis of literature of any study design on TB contact tracing in developed countries was carried out.

Setting

Any setting.

Population

Individuals found to have active TB disease, and people who have come into contact with them.

Interventions

Contact-tracing investigations.

Main outcome measures

Any outcome related to TB infection, contact investigations and/or the views of staff, people with TB disease, or their contacts.

Data sources

Searches for research published 1995 onwards were undertaken in the following databases: MEDLINE via Ovid SP, EMBASE via Ovid SP, EconLit via Ovid SP, PsycINFO via Ovid SP, Social Policy and Practice via Ovid SP, Cumulative Index to Nursing and Allied Health Literature via EBSCOhost, Science and Social Science Citation Indices via Web of Science and The Cochrane Library via Wiley Online Library.

Review methods

The study comprised a review of TB contact tracing in specific population groups and a review in wider populations. A narrative synthesis was completed and a logic model was developed from the literature.

Results

There were 112 articles in the review: 23 related to specific populations and 89 related to wider populations. The literature was of limited quality, with much general description of investigations. We identified only two (uncontrolled) studies that could be considered evaluative. Although the limitations of the evidence should be recognised, the review suggested the following: the value of a location-based approach, working with local communities and the media, partnership working, using molecular epidemiological testing, ensuring adequate systems and addressing fear of stigma. The literature on investigations for specific populations has much concordance with that reporting findings from wider population groups. The recognised limitations of conventional investigation methods may, however, be exacerbated in specific populations.

Limitations

The English-language inclusion criterion may have limited the breadth of countries represented. A meta-analysis was not possible owing to the nature of the literature. Relevant studies may have been missed by our searches, which used terminology relating to contact tracing rather than to active case finding or screening.

Conclusions

The review identified a sizeable volume of literature relating to contact investigations. However, it is currently predominantly descriptive, with little evaluative work underpinning investigations in either specific or wider populations. Our findings are, therefore, based on limited evidence. Further research is required if robust conclusions are to be made.

Future work

Research should further explore the development of measures that can be used to compare the effectiveness of different contact investigations, in studies using evaluative designs.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Effectiveness of peer educators on the uptake of mobile X-ray tuberculosis screening at homeless hostels: a cluster randomised controlled trial

TRIAL DESIGN

Cluster randomised controlled trial.

OBJECTIVE

To compare current practice for encouraging homeless people to be screened for tuberculosis on a mobile digital X-ray unit in London, UK, with the additional use of volunteer peer educators who have direct experience of tuberculosis, homelessness or both.

PARTICIPANTS

46 hostels took part in the study, with a total of 2342 residents eligible for screening. The study took place between February 2012 and October 2013 at homeless hostels in London, UK.

INTERVENTION

At intervention sites, volunteer peer educators agreed to a work plan that involved moving around the hostel in conjunction with the hostel staff, and speaking to residents in order to encourage them to attend the screening.

RANDOMISATION

Cluster randomisation (by hostel) was performed using an internet-based service to ensure allocation concealment, with minimisation by hostel size and historical screening uptake.

BLINDING

Only the study statistician was blinded to the allocation of intervention or control arms.

PRIMARY OUTCOME

The primary outcome was the number of eligible clients at a hostel venue screened for active pulmonary tuberculosis by the mobile X-ray unit.

RESULTS

A total of 59 hostels were considered for eligibility and 46 were randomised. Control sites had a total of 1192 residents, with a median uptake of 45% (IQR 33-55). Intervention sites had 1150 eligible residents with a median uptake of 40% (IQR 25-61). Using Poisson regression to account for the clustered study design, hostel size and historical screening levels, there was no evidence that peer educators increased uptake (adjusted risk ratio 0.98; 95% CIs 0.80 to 1.20). The study team noted no adverse events.

CONCLUSIONS

This study found no evidence that volunteer peer educators increased client uptake of mobile X-ray unit screening for tuberculosis. Further qualitative work should be undertaken to explore the possible ancillary benefits to peer volunteers.

TRIAL REGISTRATION NUMBER

ISRCTN17270334.

Impact of x-ray screening programmes for active tuberculosis in homeless populations: a systematic review of original studies

BACKGROUND

Tuberculosis prevalence is generally low in industrialized countries, but many cities now operate surveillance programmes to actively screen for tuberculosis in known risk groups including homeless people. While several studies have reported on individual screening programmes, this study is the first known systematic review specifically looking at chest x-ray screening programmes for tuberculosis in homeless populations.

METHODS

Systematic review of relevant studies published in the last 20 years using the PRISMA checklist.

RESULTS

Fourteen studies were reviewed: 12 cross-sectional studies, 1 retrospective cohort study and 1 'data-linkage' study. The studies were heterogenous in terms of the objectives, measured outcomes and methodological quality. Active tuberculosis prevalence was found to be higher in homeless populations and screening programmes appear to identify tuberculosis earlier, reduce prevalence and transmission, and increase treatment compliance.

CONCLUSIONS

Active x-ray surveillance programmes in homeless communities appear to be cost-effective in reducing prevalence within the homeless population particularly in related strains and may have some benefits over passive finding. While there is a need for high-quality research to further assess the impact of these programmes, this study has outlined the benefits and limitations of existing programmes and included recommendations to achieve maximum coverage, uptake and cost-benefit.

Latent tuberculosis infection screening in foreign-born populations: a successful mobile clinic outreach model

OBJECTIVES

We evaluated the efficacy of a mobile medical clinic (MMC) screening program for detecting latent tuberculosis infection (LTBI) and active tuberculosis.

METHODS

A LTBI screening program in a MMC in New Haven, Connecticut, used medical surveys to examine risk factors and tuberculin skin test (TST) screening eligibility. We assessed clinically relevant correlates of total (prevalent; n = 4650) and newly diagnosed (incident; n = 4159) LTBI from 2003 to 2011.

RESULTS

Among 8322 individuals, 4159 (55.6%) met TST screening eligibility criteria, of which 1325 (31.9%) had TST assessed. Similar to LTBI prevalence (16.8%; 779 of 4650), newly diagnosed LTBI (25.6%; 339 of 1325) was independently correlated with being foreign-born (adjusted odds ratio [AOR] = 8.49; 95% confidence interval [CI] = 5.54, 13.02), Hispanic (AOR = 3.12; 95% CI = 1.88, 5.20), Black (AOR = 2.16; 95% CI = 1.31, 3.55), employed (AOR = 1.61; 95% CI = 1.14, 2.28), and of increased age (AOR = 1.04; 95% CI = 1.02, 1.05). Unstable housing (AOR = 4.95; 95% CI = 3.43, 7.14) and marijuana use (AOR = 1.57; 95% CI = 1.05, 2.37) were significantly correlated with incident LTBI, and being male, heroin use, interpersonal violence, employment, not having health insurance, and not completing high school were significantly correlated with prevalent LTBI.

CONCLUSIONS

Screening for TST in MMCs successfully identifies high-risk foreign-born, Hispanic, working, and uninsured populations and innovatively identifies LTBI in urban settings.

Pulmonary and latent tuberculosis screening in opiate drug users: an essential and neglected approach for harm-reduction facilities

OBJECTIVES

Opiates drug users are at much higher risk of developing tuberculosis (TB) infection than general population. We conducted this study to determine the susceptibility for pulmonary and latent TB infection in opiates drug users.

METHODS

In this cross-sectional study, all opiates drug users referred to drop-in centers, methadone maintenance clinics, and harm-reduction facilities affiliated with Shiraz University of Medical Sciences in southern Iran were screened for pulmonary and latent TB infection.

RESULTS

The participation rate of opiate drug users was 87.66% (263 of 300). Mean age was 37.37 ± 8.33 (range, 20-65) years. Two hundred twenty-six (85.93%) were male and 197 (74.90%) were injection drug users (IDUs). One hundred sixty-three (61.97%) had TB-related symptoms. Culture for TB was positive in 3 patients (1.14%) (2 non-IDUs and 1 IDU). Two patients (0.76%) showed acid-fast bacilli in the direct sputum smear. Eighty-five of 244 patients (34.83%) had a 5- to 10-mm induration in the skin TB test. Twenty-nine of 223 patients (13%) had abnormal findings from chest x-ray films.

CONCLUSIONS

The prevalence of smear-positive pulmonary TB in opiate drug users is more than 100 times in the general population in Iran. Therefore, active and appropriate screening to detect pulmonary TB infection should be integrated into routine activities at all harm-reduction facilities for drug users, irrespective of their route of drug use or human immunodeficiency virus status, in this country.

Epidemiology of tuberculosis in big cities of the European Union and European Economic Area countries

This cross-sectional survey aimed to examine the epidemiology of tuberculosis (TB) in European Union (EU) and European Economic Area (EEA) cities with populations greater than 500,000. National TB programme managers were asked to provide data on big city population size, total number of notified TB cases in big cities and national notification rate for 2009. A rate ratio was calculated using the big city TB notification rate as a numerator and country TB notification rate, excluding big city TB cases and population, as a denominator. Twenty of the 30 EU/EEA countries had at least one big city. Pooled rate ratios were 2.5, 1.0, and 0.7 in low-, intermediate- and high-incidence countries respectively. In 15 big cities, all in low-incidence countries, rate ratios were twice the national notification rate. These data illustrate the TB epidemiology transition, a situation whereby TB disease concentrates in big cities as national incidence falls, most likely as a result of the higher concentration of risk groups found there. This situation requires targeted interventions and we recommend that big city TB data, including information about patients' risk factors, are collected and analysed systematically, and that successful interventions are shared.

Tuberculosis control in big cities and urban risk groups in the European Union: a consensus statement

In low-incidence countries in the European Union (EU), tuberculosis (TB) is concentrated in big cities, especially among certain urban high-risk groups including immigrants from TB high-incidence countries, homeless people, and those with a history of drug and alcohol misuse. Elimination of TB in European big cities requires control measures focused on multiple layers of the urban population. The particular complexities of major EU metropolises, for example high population density and social structure, create specific opportunities for transmission, but also enable targeted TB control interventions, not efficient in the general population, to be effective or cost effective. Lessons can be learnt from across the EU and this consensus statement on TB control in big cities and urban risk groups was prepared by a working group representing various EU big cities, brought together on the initiative of the European Centre for Disease Prevention and Control. The consensus statement describes general and specific social, educational, operational, organisational, legal and monitoring TB control interventions in EU big cities, as well as providing recommendations for big city TB control, based upon a conceptual TB transmission and control model.

The re-emergence of tuberculosis: what have we learnt from molecular epidemiology?

Tuberculosis (TB) has re-emerged over the past two decades: in industrialized countries in association with immigration, and in Africa owing to the human immunodeficiency virus epidemic. Drug-resistant TB is a major threat worldwide. The variable and uncertain impact of TB control necessitates not only better tools (diagnostics, drugs, and vaccines), but also better insights into the natural history and epidemiology of TB. Molecular epidemiological studies over the last two decades have contributed to such insights by answering long-standing questions, such as the proportion of cases attributable to recent transmission, risk factors for recent transmission, the occurrence of multiple Mycobacterium tuberculosis infection, and the proportion of recurrent TB cases attributable to re-infection. M. tuberculosis lineages have been identified and shown to be associated with geographical origin. The Beijing genotype is strongly associated with multidrug resistance, and may have escaped from bacille Calmette-Guérin-induced immunity. DNA fingerprinting has quantified the importance of institutional transmission and laboratory cross-contamination, and has helped to focus contact investigations. Questions to be answered in the near future with whole genome sequencing include identification of chains of transmission within clusters of patients, more precise quantification of mixed infection, and transmission probabilities and rates of progression from infection to disease of various M. tuberculosis lineages, as well as possible variations in vaccine efficacy by lineage. Perhaps most importantly, dynamics in the population structure of M. tuberculosis in response to control measures in high-prevalence areas should be better understood.

Food incentives improve adherence to tuberculosis drug treatment among homeless patients in Russia

The aim of the study was to evaluate the impact of food incentives on adherence to tuberculosis (TB) drug treatment among homeless patients with TB. Food packages were thus given as a part of directly observed therapy to 142 homeless patients with TB at a dispensary in Saint Petersburg, Russian Federation. In addition, a social worker provided the patients with information and legal assistance, for example help with internal passports. Among the 142 patients, 66 were included in the study at the dispensary during their entire treatment period, while 76 patients were included in the study during shorter periods mainly because of transfer to inpatient care. In the first group, 59% of the patients continued the TB drug treatment without interruption in contrast to 31% in a control group. In the second group, that is those studied during shorter periods, 95% continued the TB drug treatment without interruption while attached to the dispensary. Food was introduced in the TB programme of the City of St. Petersburg as a consequence of this study. In conclusion, it can be stated that the food incentive had a strong positive impact on the adherence to TB drug treatment among these socially marginalized patients. The social support contributed in all probability also to the positive results.

Risk factors for tuberculosis in contact investigations in Rotterdam, the Netherlands

Contact investigations around tuberculosis patients enable early detection of infection and disease, and prevention of secondary tuberculosis cases. We aim to identify risk factors for M. tuberculosis transmission to contacts of tuberculosis patients, based on unique data from routine contact investigations by the Public Health Service in Rotterdam, the Netherlands, collected between 2001 and 2006. Through logistic regression analysis, we determined the effect of various risk factors on the chance of finding a latent tuberculosis (TB) infection or overt tuberculosis case among contacts. A total of 1165 index patients with active tuberculosis were registered and at least one contact was investigated in 731, resulting in 21,540 contacts overall. Altogether, the contact investigations led to 91 cases of active tuberculosis. Of the 12,698 contacts eligible for screening by tuberculin skin test, 1091 (9%) were diagnosed with latent tuberculosis infections. Risk factors were old age of the contact, old age of the index patient, and the relationship to the index. A larger fraction of infected close contacts was strongly associated with infections among more distant contacts.

Our findings emphasize the importance of including these personal and interpersonal risk factors in decision making in contact investigations.

Tuberculosis in sheltered homeless population of Rome: an integrated model of recruitment for risk management

The authors show the results of an integrated model for risk management of tuberculosis in a sample of sheltered homeless in Rome. Tuberculin skin test (TST) was used for evaluating the prevalence of latent infection (LTBI). In TST positives, expectorate was collected and chest X-ray was achieved. Multiple logistic regression analysis was performed to investigate determinants of infection. Out of 288 recruited subjects, 259 returned for the TST reading; 45.56% were positive and referred to a specialized center; 70 accessed the health facility and completed the clinical pathway. The risk factors associated to LTBI were male gender (OR = 3.72), age over 60 years (OR = 3.59), immigrant status (OR = 3.73), and obesity (OR = 2.19). This approach, based on an integrated social network, guarantees high adherence to screening (89.93%), allowing patients testing positive for latent tuberculosis infection to be diagnosed and rapidly referred to a specialized center.

Tuberculosis among drug users and homeless persons: impact of voluntary X-ray investigation on active case finding

BACKGROUND

Illicit drug use and homelessness are major contributors to the incidence of tuberculosis (TB) among inhabitants of major cities.

OBJECTIVE

The primary objective of this study was to establish a sustainable low-threshold chest X-ray screening programme for pulmonary TB among illicit drug users and homeless persons and to integrate this into the existing public health programme for active case finding. A secondary objective was to estimate the coverage of the programme, assess other risk factors and determine TB rates and treatment outcome in these two groups.

METHODS

Illicit drug users and homeless persons were asked to voluntarily participate in an X-ray screening programme. The coverage of the intervention, total number and characteristics of cases and the follow-up of treatment were assessed.

RESULTS

A total of 4,529 chest radiographs were made from 3,477 persons, of whom 66% were homeless and 34% were illicit drug users, between May 2002 and April 2007. Coverage for screening once every 2 years ranged between 18 and 26%. Thirty-nine TB cases (14 drug users, 25 homeless persons) were identified, representing 8.7% of the total case load of 448 notified cases of pulmonary TB in Frankfurt during this period. Among the drug users, human immunodeficiency virus coinfection (10/14) seemed to play a key role in the development of TB. The case-finding rate of 861/100,000 radiographs (1,122/100,000 persons) is as high as that in routine contact investigations (1,078/100,000). Among all individuals with TB, 76% completed treatment.

CONCLUSION

A novel targeted TB screening approach with voluntary radiographic examination of illicit drug users and homeless persons can be integrated into the existing public TB prevention programme and provides a high case-finding rate.

Mycobacterium tuberculosis cluster with developing drug resistance, New York, New York, USA, 2003-2009

In 2004, identification of patients infected with the same Mycobacterium tuberculosis strain in New York, New York, USA, resulted in an outbreak investigation. The investigation involved data collection and analysis, establishing links between patients, and forming transmission hypotheses. Fifty-four geographically clustered cases were identified during 2003–2009. Initially, the M. tuberculosis strain was drug susceptible. However, in 2006, isoniazid resistance emerged, resulting in isoniazid-resistant M. tuberculosis among 17 (31%) patients. Compared with patients with drug-susceptible M. tuberculosis, a greater proportion of patients with isoniazid-resistant M. tuberculosis were US born and had a history of illegal drug use. No patients named one another as contacts. We used patient photographs to identify links between patients. Three links were associated with drug use among patients infected with isoniazid-resistant M.tuberculosis. The photographic method would have been more successful if used earlier in the investigation. Name-based contact investigation might not identify all contacts, particularly when illegal drug use is involved.

Tuberculosis infection among homeless persons and caregivers in a high-tuberculosis-prevalence area in Japan: a cross-sectional study

Background

Tuberculosis (TB) is a major public health problem. The Airin district of Osaka City has a large population of homeless persons and caregivers and is estimated to be the largest TB-endemic area in the intermediate-prevalence country, Japan. However, there have been few studies of homeless persons and caregivers. The objective of this study is to detect active TB and to assess the prevalence and risk factors for latent TB infection among homeless persons and caregivers.

Methods

We conducted a cross-sectional study for screening TB infection (active and latent TB infections) using questionnaire, chest X-ray (CXR), newly available assay for latent TB infection (QuantiFERON-TB Gold In-Tube; QFT) and clinical evaluation by physicians at the Osaka Socio-Medical Center Hospital between July 2007 and March 2008. Homeless persons and caregivers, aged 30-74 years old, who had not received CXR examination within one year, were recruited. As for risk factors of latent TB infection, the odds ratios (OR) and 95% confidence intervals (95% CI) for QFT-positivity were calculated using logistic regression model.

Results

Complete responses were available from 436 individuals (263 homeless persons and 173 caregivers). Four active TB cases (1.5%) among homeless persons were found, while there were no cases among caregivers. Out of these four, three had positive QFT results. One hundred and thirty-three (50.6%) homeless persons and 42 (24.3%) caregivers had positive QFT results. In multivariate analysis, QFT-positivity was independently associated with a long time spent in the Airin district: ≥10 years versus <10 years for homeless (OR = 2.53; 95% CI, 1.39-4.61) and for caregivers (OR = 2.32; 95% CI, 1.05-5.13), and the past exposure to TB patients for caregivers (OR = 3.21; 95% CI, 1.30-7.91) but not for homeless persons (OR = 1.51; 95% CI, 0.71-3.21).

Conclusions

Although no active TB was found for caregivers, one-quarter of them had latent TB infection. In addition to homeless persons, caregivers need examinations for latent TB infection as well as active TB and careful follow-up, especially when they have spent a long time in a TB-endemic area and/or have been exposed to TB patients.

Contribution of a shelter-based survey for screening respiratory diseases in the homeless

BACKGROUND

The homeless are at very high risk for both respiratory diseases and poor access to health care delivery systems. The aim of this study was to assess the contribution of a shelter-based survey to identify respiratory diseases in the homeless population in Marseilles, in order to further develop preventive interventions.

METHODS

A prevalence survey of respiratory diseases was conducted in two homeless shelters in Marseilles, in February 2005. A multidisciplinary team including infectious diseases specialists, lung specialists, residents, nurses, physiotherapists and X-ray technicians visited the two shelters. Interview, physical examination, sputum sampling for Mycobacterium tuberculosis detection, nasal swabs for virus detection and chest X-rays were performed in shelters. Chest X-rays were subsequently analysed by a pneumonologist and subjects found to have radiological abnormalities were hospitalized for further investigations.

RESULTS

Of the 221 homeless persons enrolled, 110/221 (50%) had at least one respiratory manifestations. Chest X-rays were abnormal in 14 persons. Active tuberculosis was diagnosed in two, influenza in two, respiratory syncytial virus infection in two, acute pneumonia in one, asthma in two, lung cancer in one, acute bronchitis in 23, chronic bronchitis in 42, and exacerbation of chronic obstructive pulmonary disease in 22 persons, respectively.

CONCLUSION

Our shelter-based survey, including clinical evaluation and chest radiographic screening, shows that this approach can be useful to control and prevent respiratory diseases among the homeless. However, further studies are necessary to determine the magnitude of influenza in the homeless, the impact of influenza immunization and optimal frequency of interventions in shelters.

Tuberculosis and illicit drug use: review and update

Illicit drug users continue to be a group at high risk for tuberculosis (TB). Here, we present an updated review of the relationship between TB and illicit drug use, and we summarize more than a decade of new research. Drug users, and injection drug users in particular, have driven TB epidemics in a number of countries. The successful identification and treatment of TB among illicit drug users remain important components of a comprehensive TB strategy, but illicit drug users present a unique set of challenges for TB diagnosis and control. New diagnostic modalities, including interferon-gamma-release assays, offer potential for improved diagnosis and surveillance among this group, along with proven treatment strategies that incorporate the use of directly observed therapy with treatment for drug abuse. Special considerations, including coinfection with viral hepatitis and the rifampin-methadone drug interaction, warrant clinical attention and are also updated here.

Estimating the coverage of a targeted mobile tuberculosis screening programme among illicit drug users and homeless persons with truncated models

Truncated models are indirect methods to estimate the size of a hidden population which, in contrast to the capture-recapture method, can be used on a single information source. We estimated the coverage of a tuberculosis screening programme among illicit drug users and homeless persons with a mobile digital X-ray unit between 1 January 2003 and 31 December 2005 in Rotterdam, The Netherlands, using truncated models. The screening programme reached about two-third of the estimated target population at least once annually. The intended coverage (at least two chest X-rays per person per year) was about 23%. We conclude that simple truncated models can be used relatively easily on available single-source routine data to estimate the size of a population of illicit drug users and homeless persons. We assumed that the most likely overall bias in this study would be overestimation and therefore the coverage of the targeted mobile tuberculosis screening programme would be higher.

Impact of Mobile Radiographic Screening on Tuberculosis among Drug Users and Homeless Persons

RATIONALE

In 2002, a mobile radiographic screening program was started in Rotterdam to respond to high rates of tuberculosis (TB) among illicit drug users and homeless persons.

OBJECTIVES

We studied trends and characteristics of TB among these risk groups and assessed the impact of the screening program on transmission, using molecular typing.

METHODS

Description of trends, and of demographic and disease-related characteristics of tuberculosis cases among these risk groups between 1993 and 2005. TB was considered to result from recent transmission if the mycobacterial DNA fingerprints of cases were identical to those of other cases in the risk groups in the previous 2 years.

MEASUREMENTS AND MAIN RESULTS

During the study period, 206 individuals with TB among illicit drug users and homeless persons were notified, representing 11.4% of the total case load of 1,811 in Rotterdam. The annual number of tuberculosis cases declined from 24 at the start of the screening program to 11 cases in 2005. The screening program identified 28 cases (a prevalence rate of 327 per 100,000 radiographs), of which 12 were smear positive. In 1997-2002, more than 80% of the illicit drug users or homeless persons with TB were infected with one of the Mycobacterium tuberculosis strains prevalent among these risk groups. After nearly 4 years of systematic radiographic screening this proportion declined to 45% in 2005.

CONCLUSIONS

DNA fingerprinting can be a useful tool to evaluate the impact of a TB screening program. We advocate that screening of illicit drug users and homeless persons should be continued to prevent a resurgence of TB.

Tuberculosis in London: the importance of homelessness, problem drug use and prison

BACKGROUND

The control of tuberculosis (TB) is founded on early case detection and complete treatment of disease. In the UK, TB is concentrated in subgroups of the population in large urban centres. The impact of homelessness, imprisonment and problem drug use on TB control in London is reviewed.

METHODS

A cohort study was undertaken of all patients with TB in Greater London to determine the point prevalence of disease in different groups and to examine risk factors for smear positivity, drug resistance, treatment adherence, loss to follow-up and use of directly observed therapy (DOT).

RESULTS

Data were collected on 97% (1941/1995) of eligible patients. The overall prevalence of TB was 27 per 100,000. An extremely high prevalence of TB was seen in homeless people (788/100,000), problem drug users (354/100,000) and prisoners (208/100,000). Multivariate analysis showed that problem drug use was associated with smear positive disease (OR 2.2, p<0.001), being part of a known outbreak of drug resistant TB (OR 3.5, p = 0.001) and loss to follow-up (OR 2.7, p<0.001). Imprisonment was associated with being part of the outbreak (OR 10.3, p<0.001) and poor adherence (OR 3.9, p<0.001). Homelessness was associated with infectious TB (OR 1.6, p = 0.05), multidrug resistance (OR 2.1, p = 0.03), poor adherence (OR 2.5, p<0.001) and loss to follow-up (OR 3.8, p<0.001). In London, homeless people, prisoners and problem drug users collectively comprise 17% of TB cases, 44% of smear positive drug resistant cases, 38% of poorly compliant cases and 44% of cases lost to follow-up. 15% of these patients start treatment on DOT but 46% end up on DOT.

CONCLUSIONS

High levels of infectious and drug resistant disease, poor adherence and loss to follow-up care indicate that TB is not effectively controlled among homeless people, prisoners and problem drug users in London.